In one of the older version (I think 2.0 on iOS) I remember there being a notebook feature that would let me see all of my marked scriptures at once, but I for the life of me can't find anything like that in the current version.

While this is a planned feature, it is not yet in the released version of the application. A preview of it, what we're calling the "Annotations Pane", can be found in an elementary form in the beta version of the app, available on the Windows Store.

Have a bug to report for Gospel Library for Windows v4? Check the Known Issues to see if it's been reported. (https://tech.lds.org/wiki/Gospel_Library_for_Windows_Preview_Issues)Also visit the FAQ. (tech.lds.org/wiki/Gospel_Library_for_Windows_8_FAQ)